The goal of this two-year continuation is to map and clone genes associated with autosomal dominant forms of retinitis pigmentosa (adRP). At present, more than 250 families with adRP have been analyzed as part of a systematic linkage and mutation analysis. Fifteen large families suitable for linkage analysis have been identified. None of these families have mutations in known RP-associated genes. Linkage analysis and mutation screens will be carried out to map and characterize these new adRP families. Completion of this project will help to delineate the types and prevalence of mutations that lead to adRP in a large and diverse sample of Americans. A more complete understanding of the molecular causes of RP may foster the development of novel therapies for this disease.